Firefox still uses more memory than most other web browsers. Truthfully, the amount it uses is ridiculous. Firefox can use up to 500MBs of memory if you keep it running. In addition, you will see that the memory usage keeps rising because of, you guessed it, memory leaks. Some Firefox users even reported memory usage over 1000MBs. That is half of the memory gone on most computers.
A solution to this issue is Firemin, a simple application that can help you eliminate all the memory leaks of Firefox. Firemin uses a safe API function called EmptyWorkingSet that basically forces the process (in this case Firemin) to use less memory. Other words, tells Firefox to give back some of the system memory it's hanging on to. Using this function will sometimes result in a slight performance decrease measured in milliseconds , but I do mean slight, the chance of you noticing the performance decrease is almost zero.
Whats new:>> Added: High resolution icon (256x256px).
Updated: Japanese translation.
Updated: Optimized browser Safe Mode detection.
Fixed: Incorrect default values.
Fixed: Main windows not being able to close.
Fixed: Workarounds added to alleviate slow downs on Windows 10 1809 and later.
http://www.rizonesoft.com/downloads/firemin/